1. Field of the Invention
This invention concerns neuro-stimulation, that is artificial electrical stimulation of body tissues using a device implanted in the body. In particular the invention concerns a distributed implantable neuro-stimulation apparatus, an electrode cell forming part of the apparatus, an implant controller forming part of the apparatus, a method of applying neuro-stimulation, and a signal for use in the method.
2. Description of Related Art
Perhaps the pacemaker is the best known tissue stimulator. It is implanted in the chest and a single electrode is connected to the heart to regulate the rate of beating. Cochlear implants are neuro-stimulators used to restore hearing. They are more complex than heart pacemakers and involve an implant controller that contains all the active electronic components, as well as twenty or so passive electrodes individually connected to the controller. The controller is sealed inside a titanium shell which has hermetic ceramic or glass feed-throughs fitted with a pin for each passive electrode. The electrodes are made from platinum and silicone, and are connected back to the controller by individual conductors. The electrodes are implanted adjacent respective parts of the cochlear to stimulate the auditory nerve.